Abstract: A transmission system of embodiments is a transmission system including a plurality of transmission stations connected together via a single transmission path. Each transmission station includes a sending controller, an obtaining unit, and a first storage. The obtaining unit is configured to obtain first information regarding sending or reception of a communication frame in synchronization with sending or reception of the communication frame. The first storage is configured to store the first information and second information indicating the date and time of obtaining the first information.

Abstract: A transmission system of embodiments is a transmission system including a plurality of transmission stations connected together via a single transmission path. Each transmission station includes a sending controller, an obtaining unit, and a first storage. The obtaining unit is configured to obtain first information regarding sending or reception of a communication frame in synchronization with sending or reception of the communication frame. The first storage is configured to store the first information and second information indicating the date and time of obtaining the first information.

Abstract: A communication system includes a plurality of communication devices that transmits shared data in turn through wireless communication. Each of the communication devices includes a shared memory, a transmission processor, a reception processor, and a data comparator. The shared memory is capable of storing shared data for each of the communication devices. The transmission processor transmits the shared data of the communication device stored in the shared memory to a second communication device as another communication device. The reception processor monitors data as the shared data received by the second communication device from the communication device and transferred to a third communication device as another communication device other than the second communication device, and receives the data as monitored data. The data comparator compares the received monitored data with the data previously transmitted to the second communication device.